All just my personal opinion
Mozart: Rondo in A for Piano & Orchestra, K.386 — Clara Haskil, Bernhard Paumgartner, Wiener Symphoniker / Vladimir Ashkenazy, István Kertesz, London Symphony Orchestra / Kristian Bezuidenhout, Petra Müllejans, Freiburger Barockorchester
Telemann: 12 Fantasias for Flute — comparing recordings with the following artists: Barthold Kuijken (traverso), Dan Laurin (recorders), Leif Ramløv Svendsen (recorder), Maurice Steger (recorders), Dorothee Oberlinger (recorders), Héloïse Gaillard (recorders), Maxence Larrieu (Böhm flute), François Leleux (oboe), Kevin Thompson (euphonium)
Der Ring des Nibelungen, part 4 — comparing 2 recordings: Furtwängler (1953, Rome), with Suthaus, Mödl, Greindl, Poell, Jurinac, Klose, Pernerstorfer, etc.; Janowski (1980), with Kollo, Altmeyer, Salminen, Nöcken, Sharp, Wenkel, Nimsgern, etc.
Lieder recordings (Beethoven & Schumann) with Fischer-Dieskau/Moore, Wunderlich/Giesen, Goerne/Schneider, Terfel/Martineau, Bostridge/Drake; Schumann: Piano Quintet op.44, Piano Quartet op.47 — Melnikov/Jerusalem Quartet, Levine/LaSalle Quartet; Webern: 6 Bagatellen, 5 Movements for string quartet, op.5 — Hagen Quartett
Beethoven: 6 Bagatelles, op.126 — Ashkenazy (1984), Brautigam (2010), Brendel (1964 & 1985), Gould (1974), Schnabel (1937); Beethoven: 24 Variations on the Arietta “Venni Amore” by Vincenzo Righini, WoO 65 — Pletnev (1997), Brautigam (2012); Schubert: Symphony in B minor, D.759 (“Unfinished”) / Symphony in C major, D.944 (“Great C major”) — Furtwängler (1952), Harnoncourt (1992), Dausgaard (2006)